iii 





r-iii: 



UNITED STATES DEPARTMENT OF AGRICULTURE 

Ik BULLETIN No. 599 



J^-'^^u 



Contribution from Bureau of Entomology 
L. O. HOWARD, Chief 




Washington, D. C. 



PROFESSIONAL PAPER 



March 16, 1918 



THE STRIPED PEACH WORM/ 

By H. G. Jngekson, Scientific Assistant, Deciduous Fruit Insect Investigations. 



CONTENTS. 



Introduction 1 

History 2 

Synonymy 2 

Food plants 3 

Feeding habits of tlie larva 3 

Character of injury on peach 3 

Character of injury on sand cherry 3 

Description 4 

The adult 4 

The egg 4 



Description— Continued. 

The larva 4 

The pupa 5 

The cocoon 5 

Seasonal history and habits 5 

Summary of seasonal-history studies 11 

Parasites 12 

Remedial measures 13 

Literature cited 14 



INTRODUCTION. 



The striped peach worm {Gelechia confuselTa Cham.), although 
described in 1875, has received little notice as an economic species. 
The larvffi feed in conspicuous webs on the foliage of the peach and 
on sand cherry {Primus pumila) in smaller but more compact webs. 
While at present this insect is not a major pest on peach, the larvae 
have been observed feeding on sand cherry in such numbers as to 
web nearly every terminal, partially defoliating the host plant, 
and this shows the latent possibility of extensive injury to peach or- 
chards. 

Under the direction of Dr. A. L. Quaintance, Entomologist in 
Charge of Deciduous Fruit Insect Investigations, the writer studied 
the biology and habits of tlie insect during the seasons of 1915 and 
1916. The biological data secured, together with descriptions of all 
the stages and suggestions for control, are recorded in this paper. 

^ The writer is indebted to the following members of the Bureau of Entomology staff : 
To E. H. Siegler for the photograph used in Plate I, figure 1 ; to H. K. Plank for Plate 
II, figure 1, and Plate III, figures 1, 2, and 3 ; to J. H. Paine for Plate II, figures 2 and 
3, and to F. L. Simanton for determining the place of oviposition on sand cherry and 
for conducting the. spraying work in connection with the remedial measures. 
11918°— 18 



2 BULLETIN 599, U. S. DEPARTMENT OF AGRICULTURE, 

The life-history studies were started at Benton Harbor, Mich., in 
1915 and completed in 1916. 

Adults were reared separately from larva? collected on the two host 
plants and were identified as Gelechia confusella, by Mr. August 
Busck, of the Bureau of Entomology. 

HISTORY. 

The adult of Gelechia confusella was first described by Chambers 
(1)' in 1875, but with no mention of the source of his material. 
Pettit (4), under the heading "A new peach worm," writes as 
follows : 

A number of worms working in peach leaves were received from Mr. T. D. 
Atkinson, of Holland, Mich., on September 17. They were lepidopterous larvae 
and were said to be very troublesome. The same species was received on July 
3, 1899, from Monroe, Mich. One or two complaints were made from other 
places, though no specimens were sent. 

These are apparently the only published accounts of the occurrence 
of this insect. 

SYNONYMY. 

In 1899 Pettit (4) described the larva of this insect and figured 
the larva and pupa, designating them "Peach leaf-binder, Depres- 
saria persicaeella Murt." In the same publication (5) the adult is 
described as Depressaria persicaeella by Miss Mary E. Murtfeldt, of 
Kirkwood, Mo., from material sent her by Mr. Pettit. Miss Murt- 
feldt (6) changes Depressaria persicaeella Murt., to Gelechia. 

Dyar (7) lists Gelechia confusella Cham., with persicaeella Murt. 
as a synonym. Busck (8) lists Gelechia confusella Cham, with 
synonyms Depressaria persicaeella Murt. and Gelechia persicaeella 
Murt., and makes the following note: 

Cotypes of Miss Murtfeldt's species are in the United States National Mu- 
seum imder type No. 4697. The species is very close to the foregoing, and I 
have no doubt is the same as Chambers's Gelechia confusella, the type of which 
is lost but the description of which tallies in every detail with the peach feeder. 

In 1904 Pettit (9), under the name "The striped peach-worm 
( Gelechia confusella) ," copied part of his former description and re- 
produced the figures of the larva and pupa of 1899, designating them 
as the " striped peach-worm." The synonymy stands : 

Gelechia confusella Cham., 1875. 

Depressaria persicaeella Murt.. 1890. 
Gelechia, persicaeella Murt., 1900. 

The writer has accepted the name " striped peach Avorm," as it 
seems to distinguish this insect from all other peach feeders and 
briefly describes the larva, which is the only stage commonly seen. 

1 Reference is made by number to " Literature cited," p. 14. 



D. of D,- 
APi^ 15 19J8 






THE STRIPED PEACH WORM. 



FOOD PLANTS. 



Previously published notes have recorded G. confusella as feed- 
ing only on peach foliage. During July, 1915, the writer observed 
a Avebbed condition on sand cherry {Primus puTnila) (PL IV) 
which resembled somewhat the injury already noted on peach (PI. 
I), though the webs were more tightly bound and less silk was ob- 
servable. The injury was so extensive and uniform over a sand- 
cherry thicket of about 15 acres in extent at this place near St. 
Joseph, Mich., that it seems probable that this is the native host plant 
of the insect. 

FEEDING HABITS OF THE LARVA. 

The larva feed either singly or gregariously on both host plants, 
and, though not voracious feeders, by their well-developed web- 
bing habit include in their webs much foliage that is not used as 
food. The larvae begin webbing directly after hatching, even before 
they feed, and usually spin the first thin white web on the underside 
of the leaves next to the midrib. They begin feeding next to the 
midribs of the leaves, first eating small irregTilar holes through the 
parenchyma and later skeletonizing either or both leaf surfaces. 

CHARACTER OF INJURY ON PEACH. 

The injury to the peach is caused by the feeding of the larvse on 
the foliage. The webs spun by the larvae are loose, with considerable 
silk showing, and are often very conspicuous. The leaves soon be- 
come dry and cease to function, when included in the webs. 

CHARACTER OF INJURY ON SAND CHERRY. 

The webs on the sand cherry are small and compact, with only a 
little silk showing, but in the fall the infested terminals and branches 
become prematurely brown and conspicuous. Feeding is confined to 
the foliage, and, although in rare instances the webs are constructed 
about fruit, in no cases have larvae been observed to feed on the 
fruit. Larvae of varying sizes are found in the same webs, indicat- 
ing the probability of repeated oviposition in the same terminal. 
From 2 to 12 larva? are usually found in the webs on the separate 
terminals, although the number is sometimes as high as 30. In most 
cases observed when there was only one web on a branch it was 
located at the terminal, but when more than one was present the 
webs started from the base as well as from the terminal. As the 
larvae enlarge the webs, they extend them along the branches, gradu- 
ally including more and more foliage. 



4 BULLETIN" 599, U. S. DEPARTMENT OF AGEICULTURE. 

DESCRIPTION. 

THE ADULT. 

(PI. Ill, fig. 3.) 

Because of its completeness the description of the adult is copied 
from Murtfeldt: 

Antennae dark fuscous, indistinctly pectinate and banded on the under side 
witli pale buff. Palpi long, exceeding the vertex. Basal joint short, pale ; sec- 
ond joint one-third longer than apical. Bitish quite dense, distinctly divided, 
dark fuscous overlaid with cream-coloured scales, palest on inner side. Apical 
joint dark, very slender, with extreme tip cream white, most conspicuously so in 
$. Tongue long, sparsely scaled. Vertex dark brown. Face cream white. 
Thorax and teguUe purplish-brown. Fore wings almost black, with rich purplish 
gloss, and sparsely sprinkled with white scales. On the costa back of the apex 
is a small, irregularly triangular, cream white spot, and a few scattered scales 
of the same colour form an obscure outer border. In the cell near its upper mar- 
gin are two somewhat indefinite, cream-coloured dots in line, with a third one 
below and slightly back of the one nearest the base. Cilia fuscous, shading 
outward to gray. Lower wings shining silky, cinereous, almost silvery. Abdo- 
men pale brown, terminal segment banded with buff at posterior margin. Lat- 
eral tufts buff, inconspicuous; anal tuft reddish-brown. Under surface spec- 
kled with brown and cream. Legs brown, annulate with cream white at the 
joints and middle of the tibiae. Alar expanse from 16 to 17 mm. 

THE EGG. 

(PI. II, fig. 3.) 

The egg is bluntly elliptical, somewhat flattened at the smaller 
attached end ; length, 0.57 mm. ; greatest width, 0.42 mm. The color 
is clear white when newly deposited, changing within 24 hours to a 
creamy yellow, the surface smooth and shiny without markings. 
About 24 hours before hatching the eggs change to a pearl gray color. 

THE LARVA. 

(PI. II, fig. 1.) 

The newly hatched larva is about 1.5 mm. in length and is yellow- 
ish white in color, with, head and thoracic shield fuscous. The reddish 
brown stripes are discernible after about 9 days and as they develop 
they give color to the larva. A detailed description of the full-grown 
[arva is copied from Pettit : 

The larva, when full grown, is three-eighths of an inch in length and quite 
slender. Its color is dirty yellowish- white with back and sides marked by 
six reddish-brown longitudinal stripes all of which extend the entire length 
from the thoracic shield to the caudal extremity except the pair on the 
dorsum which unite on the last segment and terminate there. Last segment 
bordered caudally with fuscous and base of anal pro-legs colored the same. 
Venter marked along the middle with a stripe like those on dorsum and sides, 



THE STRIPED PEACH WORM. 5 

which ax'e about equidistant from each other and of about the same width 
as the spaces between them, color reddisli-brown. Some of the spaces (yellow- 
ish-white) have dark points in them. Head and thoracic shield yellowish- 
brown, feet fuscous and dirty yellow. Four pairs of pro-legs beside anal pair 
which are of the same color as the ground color of the body. Base of anal 
pair black. 

Mature larvse (PI. II, fig. 1) were found to vary from three- 
eighths to five-eighths inch in length, and in color to vary from 
yellowish white with poorly defined stripes to a clear white with 
vivid venetian-red stripes. There is an anteriorly directed semi- 
circular black patch over each ocellar area. 

THE PUPA. 

(PI. Ill, fig. 1.) 

The pupa is unusually broad across the thoracic region, slightly 
flattened dorso-ventrally and quite variable in size. The average di- 
mensions of 10 were found to be 6.3 mm. by 2.6 mm. When newly 
formed, the pupa is a light brown, changing later to a dark brown, 
the head, thorax, and ventral region obtaining a much darker color 
than the other regions. The wing pads are long, extending to cover 
all but the 3 posterior segments of the abdomen. 

THE COCOON. 

(PI. Ill, flg. 2.) 

This species differs from many of the genus in that it pupates nor- 
mally in the soil. The larva enters the soil to a depth of about one- 
half inch and spins a white silken cocoon, which it incloses in fine 
soil particles and to the outside attaches coarser particles. Within 
this cocoon the larva pupates. The average size of 38 cocoons meas- 
ured was 9.3 mm. in length by 4.4 mm. at the greatest width, slightly 
flattened to conform to the pupa3 and usually distinctly curved. 

SEASONAL HISTORY AND HABITS. 

The following seasonal-history records were started at Benton 
Harbor, Mich., during the season of 1915 and were completed in 1916, 
in open-air insectaries in which glass battery jars were used as rear- 
ing cages. In all cases peach foliage was used as food for the larvae. 
There is one full brood and a partial second brood. 

The rearing studies began with the collection of a quantity of 
larvae September 3, 1914. These overwintered, and the moths which 
emerged were used for part of the 1915 records. The rearing ma- 
terial for 1916 was that kept from the season of 1915, together with 
moths emerging from pupae collected in May, 1916. 



6 



BULLETIN 599, U. S. DEPARTMENT OF AGRICULTURE. 



EMERGENCE OF SPRING BROOD OF MOTHS, 1916. 

The earliest emergence of moths took phice on May 22 and be- 
ginning on June 5 was quite regular until July 14, with the maxi- 
mum emergence on June 29. 

Table I. — Emergence of spring Jjrood of moths of the striped peach worm in 1916. 



Date of 
observation. 


Number 
of moths. 


Date of 
obseryation. 


Number 
of moths. 


Date of 
observation. 


Number 
of moths. 


Date of 
observation. 


Number 
of moths. 


May 22 

May 30 

June 5 

June 6 

June 8 

June 10 

June 11 


1 
2 
1 
4 
5 

3 


June 13 

Jime 15 

June 17 

June 18 

June 21 

June 23 

June 25 


12 
30 
24 
21 
56 
43 
17 


June 29 

July 2 

July 4 

Julys 

Julv7 

July 10 

July 12 


60 
32 
14 
3 
18 
4 
2 


July 13 

July 14 

Total... 


3 
3 


364 



OVIPOSITION OF SPRING BROOD OP MOTHS. * 

As the moths emerged they were placed in jars with peach foliage 
and fruit. The moths oviposited freely in confinement whenever 
fruit was supplied in the oviposition jars. The eggs were deposited 
both on the fruit (PI. II, fig. 2) and under the scales surrounding the 
attachment of the peach to the stem. In a single instance one egg was 
found in the axil of a peach leaf. On the sand cherry the eggs were 
found under the bud scales at the base of the current season's growth 
and in the axils of the leaves as indicated by the circles shown in 
Plate IV, figure 1, a. The occurrence of the eggs on the peach under 
orchard conditions was not noted. From Table III it will be seen 
that in 1915 eggs were being deposited in the jars from June 2 until 
June 26. 

LENGTH OF LIFE OF MOTHS OF SPRING BROOD. 

The length of life of 20 adults which were provided with a weak 
solution of clarified honey for food is shown in Table II. 



Table II.- 



-Lcngih of life of 20 moths of the spring hroocl of the striped peach 
tvorm, 1916. 



Number of 
moths. 


Days of 
life. 


Number of 
moths. 


Days of 
life. 


1 
5 
5 
4 


4 
6 
9 
12 


3 

1 
1 


14 
16 

28 


20 



Maxin-um length of life days. . 28 

Minimum length of life do 4 

Average length of life do 10. 6 



THE STRIPED PEACH WORM. 7 

The average length of life of the adults is seen to be 10.6 days. 
From observations made in 1915, however, one adult was found to 
live 31 days, and eight moths emerging previous to May 24 were 
alive a month later.. These moths were not supplied with food. 

HABITS OF THE MOTHS. 

The adults are not often seen in the field because of their small 
size and inconspicuous coloring. They are difficult to follow when 
seen because of their habit of short irregular flights and their re- 
semblance when at rest to the color of the twigs of the host plant. 
The characteristic resting position is shown in Plate III, figure 3, 
from a photograph of a live specimen. One pair of adults was ob- 
served in copulation in a rearing cage on June 21, 1916, at 10.30 
a. m. The heads of the male and female were in opposite directions 
and no parts were in contact except the genital organs. Both moths 
remained quiet during copulation. 

FIRST BROOD. 

Incubation. 

In Table III the incubation period for the eggs deposited each day 
is shown. It w^ill be seen that there was a variation of from 10 to 
19 days in the incubation period, and even with eggs deposited the 
same day on the same fruit and thus subjected to the same external 
conditions there was a variation of five days. The average length 
of the incubation period was 13.18 days. 



Table III.- 



-Inciihation period of first-brood eggs of the striped peach worm at 
Benton Harbor, Mich., 1915. 



Date of 

oviposi- 

tion. 


Number 
of eggs 
depos- 
ited. 


Date of 
batching. 


Number 
of larvae. 


Egg stage. 


Date of 

oviposi- 

tion. 


Number 
of eggs 
depos- 
ited. 


Date of 
hatching. 


Number 
of larvee. 


Egg stage. 


June 2. . . 
June 3. . . 
Junes... 

June 6... 

Jime 10. . 


11 
6 
4 

28 

2 
20 
3 


Jmie 15 . 
(June 16.. 
{June 19.. 
(June 20.. 

Jmie21.. 
fjime20.. 
1 June 23.. 
) June 24.. 
(June 25.. 

Jime23.. 

Jime26.. 

June 27.. 


11 
1 
2 
1 
3 

23 
1 
3 
1 
2 

20 
2 


Days. 
13 
13 
14 
15 
16 
14 
17 
18 
19 
13 
14 
15 


June 16. . 

June 18.. 

June 20.. 
June 20.. 

Total . . 


6 

29 

4 
5 


(Jime26.. 
{Jime27.. 
1 June 28.. 
Jmie28.. 
1 June 29.. 
jJvmeSO.. 
(Julyl... 
June 30.. 
July?... 


2 
2 
1 

10 
13- 
5 
1 
2 

1 


Days. 
10 
11 
12 
10 
11 
12 
13 
10 
11 


118 


107 




June 12.. 







Maximum egg stage days.. 19 

Minimum egg stage do 10 

Average egg stage do 13. 18 



BULLETIN 599, U. S. DEPARTMENT OF AGEICULTUKE. 



Feeding Period of Fiest-Bkood Larv^. 

The feeding period of the larvae in the rearing cages in 1915 ex- 
tended from June 15 to August 5. In 1916, larvae were feeding from 
June 22 until August 1 as shown in Tables IV and V. The longest 
feeding period recorded was 48 days, the shortest 22 days, and the 
average 29.6 days for transforming larvae, and 34.2 days for over- 
wintering larva?. On July 28, 1915, the writer came upon the in- 
jury on sand cherry. The infestation was at its height and prac- 
tically all the insects in the larva stage. By August 11 about one- 
half the larvae had left the webs and newly formed pupae were to 
be found in the soil. Observations made on September 14 showed 
that from 95 to 98 per cent of the larvae had left the webs. 

Table IV. — Length of feeding period of transforming first-brood larvce of the 
striped peach icorm, 1916. 



Date of hatching. 


Date of 

ofcocoon- 

ing. 


Number 
of 

COCOOILS. 


Days of 
feeding. 


Date of hatching. 


Date of 

cocoon- 

Ing. 


Number 

of 
cocoons. 


Days of 
feeding. 


June 22 


July 20 
July 22 
July 24 
July 26 
July 27 
July 28 


1 
3 
1 

1 
2 

1 


28 
30 
32 
34 
35 
36 




July 17 
July 20 
July 26 


2 


22 


Do 


Do. 


25 


Do 


Do 


31 


Do 


Total . . . 




Do 


14 




Do 













Maximum length of feeding period days. . 36 

Minimum length of feeding period do. . 22 

Average length of feeding period do. . 29. 6 

Table V. — Length of feeding period of wintering first-J)rood larvce of the striped 

peach tvorm, 1916. 



Date of hatching. 


Date of 

cocnon- 

mg. 


Number 

of 
cocoons. 


Days of 
feeding. 


Date of hatching. 


Date of 

cocoon- 

ing. 


Number 

of 
cocdons. 


Days of 
feeding. 


June 22 


July 20 
July 23 
July 24 
July 27 
July 28 
July 31 
July 30 
Aug. 8 


2 

1 
2 
1 
4 
3 
2 
1 


28 
31 
32 
35 
36 
39 
38 
47 


June 22 


Aug. 9 
July 17 
July 26 
July 31 
Aug. 1 


1 
1 
3 
1 

1 


48 


Do. . 


June 25 


22 


Do 


Do 


31 


Do 


July 5 


26 


Do 


Do 


27 


Do 


Total.. 




Do 


23 




Do 













Maximum length of feeding period days.. 48 

Minimum length of feeding period do . . 22 

Average length of feeding period do.. 34.2 

CocooNiNG OF First Brood. 

Cocooning takes places in the soil at an average depth of one-half 
inch, in fine sandy loam in the rearing cages, and this was found to be 
the usual depth in the soil in the field where the pupae were found. 
Of a total of 203 individuals recorded, 31 pupated on the surface of 
the soil, 154 in the upper half inch, 18 in the second half inch, 



Bui. 599, U. S. Dept. of Agriculture. 



Plate 




Work of the Striped Peach Worm (Gelechia confusella). 

Injury to peach foliage and characterist ic webbing. From pliotograph of limb taken from orchard 
About one-half natural size. (Original.) 



Bui. 599, U. S. Dept. of Agriculture. 



Plate II. 




The Striped Peach Worm (Gelechia confusella). 

Fig. 1.— Views of larvae: o, Dorsal; b, lateral; c, ventral. All enlarged about 6 times. Fig. 2. 
Eggs on peach, about natural size. Fig. 3.— Eggs enlarged about 11 times. (Original.) 



Bui. 599, U. S. Dept. of Agriculture. 



Plate III. 





The Striped Peach Worm (Gelechia confusella). 

Fig. 1. — Views of pupae: a,- Lateral; b, dorsal; c, ventral. Enlarged about 9 times. Fig. 2.— 
Pupal case, enlarged about 10 times. Fig. 3. — Adult, enlarged about 11 times. From photograph 
of living specimen showing natural position when at rest. (Original.) 



Bui. 599, U. S. Dept. of Agriculture. 



Plate IV. 




Work of the Striped Peach Worm (Gelechia confusella). 

Fig. 1. — a. Sand cherry terminal uninjured. Circles indicate place of egg deposition, b, Sand cherry 
terminal in early stage of injury by larvae, lowest leaf showing skeletonizing. Fig. 2. — Sand cherry 
terminal completely webbed by larvae. All reduced about one-third. (Original.) 



THE STRIPED PEACH WORM. 



9 



and none deeper. The larvae in the rearing cages cocooned from July 
17 to August 9, but nearly full-grown larvae collected on sand cherry 
August 11 were cocooning from August 12 until September 14. The 
dates of cocooning for the season of 1916 are shown in Tables IV 
and V, and the length of the period in the cocoon for 17 individuals 
is shown in Table VI. The average length of the period in the 
cocoon was determined to be 12.4 days; the longest period, 21 days; 
and the shortest period, 9 days. 

Table VI. — Length of time spent in the cocoon by the first hrood of the striped 

peach icortn, 1916. 



Date of cocooning. 


Number 

of 
cocoons. 


Date of 
moth 
emer- 
gence. 


Days in 
cocoon. 


Date of cocooning. 


Number 

of 
cocoons. 


Date of 
moth 
emer- 
gence. 


Days in 
cocoon. 


July 17 


2 
3 
2 
1 
1 
1 
2 


July 2S 
Aug. 1 
Aug. 2 
Aug. 4 
Aug. 6 
Aug. 4 
...do.... 


11 
12 
11 
13 
13 
10 
9 


July 27. 




Aug. 7 
Aug. 9 
Aug. IS 

...do.... 

...do.... 


11 


July 20 


Do.. 


13 


July 22 


July 28 


21 


Do 


Aug. 1 . 


17 


July 24 


Aug. 3 


15 


July 25 


Total 




July 26 


17 













Maximum length of time in the cocoon days. . 21 

Minimum length of time in the cocoon do.. 9 

Average length of time in the cocoon do. . 12.4 



Emergence of Fiust-Brood Moths. 



Table VII. 



-Emergence of first-brood moths of the striped peach tvorm at 
Benton Harbor, Mich., 1915. 



Date of emergence. 


Number of moths. 


Date of emergence. 


Number of moths. 


Aug. 4 


Male. 






3 




Female. 
4 
1 
3 
4 
3 
9 
1 
2 
1 


Aug. 16 


Male. 

1 
1 

1 
1 


2 


Female. 
3 


2 
1 

2 
1 
3 




Aug. 20 


Aug. 6 


Aug. 21 




Aug. 27 


Aug. 9 


Aug.2S 


Aug. 10 


Aug. 29 


Aug. 11 


Sept. 1 


Aug. 12 


Sept. 11 


Aug 14 . . 


Sept. 12 




Total 


9 


40 



Table VII shows that first-brood moths were emerging irom 
August 4 until September 12 in 1915, with the largest number on 
August 10. From 683 larvse collected on sand cherry July 28 only 
two moths subsequently emerged that season — one on August 28 and 
the other on September 9. The dates of emergence of first-brood 
moths in 1916 are shown in Table VI. 



10 BULLETIN 599^ U. S. DEPAETMENT OF AGEICULTUEE. 

OviPOSiTioN OF First-Beood Moths. 

Table VIII. — Oviposition of flrst-brond moths of the striped peach tvorm at 
Benton Harbor, Mich., 1915. 



Date of 
oviposition. 


Number 
of eggs. 


Date of 
oviposition. 


Number 
of eggs. 


Aug. 15 . 


178 
26 
10 


Aug. 18 


13 
10 


Aug. 16 


Aug. 19 


Aiif 17 


Total 




237 



It will be seen from Table VIII that eggs were being deposited 
from August 15 until August 19, with the greatest number on August 
15. The oviposition records are from the moths recorded in Table 
VII ; the late emerging moths failed to oviposit. On the morning of 
August 19, in transferring a peach on which eggs had been depos- 
ited, by mistake one moth was transferred. When the condition of 
the eggs was observed on the morning of xVugust 23 the moth had 
deposited 42 eggs in addition to those previously recorded. 



second brood. 

Incubation Peeiod of Second-Brood Eggs. 

Table IX. — Incubation period of second-brood eggs of the striped peach worm 
at Benton Harbor, Mich., 1915. 



Date of ovi- 
position. 


Number 
of eggs. 


Date of 
hatching. 


Number 
of larvae. 


Egg 
stage. 


Aug. 16 


26 


Aug. 31 
Sept. 1 
Sept. 2 
Sept. 3 
Sept. 5 
Sept. 1 
Sept. 2 
Sept. 3 
Sept. 3 


14 
2 
3 
1 

4 
5 

8 
1 
17 


Days. 
15 
16 
17 

18 
21 
15 
15 
16 
15 


Aug. 17 








11 
13 


Aug. 18 


Aug. 19 


17 


Total 


67 




55 









Maximum length of incubation period days. . 21 

Minimum length of incubation period do'. ... 15 

Average length of incubation period do 15.6 

In Table IX it will be seen that eggs began to hatch on August 31 
and continued to hatch until September 3; the average incubation 
period being 15. G days. 

The Emergence of the Larva From the Egg. 

The larva cuts the top of the eggshell with its mandibles and eats 
the part cut away. By a wriggling movement it forces its head and 
thoracic legs out of the shell and with these legs on the edge of the 
shell pushes the rest of the hodiy out by the use of the caudal part 
of the abdomen. Of four individuals observed, 13 minutes was con- 



THE STRIPED PEACH WORM. 



11 



sumed by each from the first cutting of the eggshell until the larva 
was entirely free. 

Feeding Period of Second-Brood Larv^. 

Table X. — Length of feeding period of seeond-brood Inrvw of tJie striped peach 
worm at Benton Harbor, Mich., 1915. 



Date of hatching. 


Date of 

cocoon- 

ing. 


Number 

of 
cocoons. 


Days 

of 

feeding. 


Date of hatching. 


Date of 

eocoon- 

ing. 


Number 

of 
cocoons. 


Days 
feeding. 


Aug. 23 


Oct. 7 
Oct. 9 
Oct. 12 
Oct. 15 
Oct. 24 
Oct. 30 
Oct. 9 
Oct. 12 
Oct. 24 
Oct. 12 
Oct. 22 
Oct. 15 


10 
14 
1 
1 
1 
1 
4 
2 
11 
2 
8 
1 


45 
47 
50 
53 
62 
68 
39 
42 
54 
41 
51 
44 


Sept. 1 


Oct. 24 
Oct. 27 
Oct. 30 
Nov. 2 
Nov. 10 
Nov. 14 
Oct. 22 
Oct. 24 
Oct. 12 
Oct. 24 


2 
2 
1 

3 
8 
2 
4 
1 
1 
1 


53 


Do 


Do 


56 


Do 


Do 


59 


Do 


Do 


62 


Do 


Do 


70 


Do 


Do.. 


74 


Aug. 31 


Sept. 2 


50 


Do 


Do 


52 


Do 


Sept. 3 


39 


Sept. 1 


Do 


51 


• Do 


Total 




Do 




81 













Maximum length of feeding period days. . 74 

Minimum length of feeding period do 39 

Average length of feeding period do 52. 1 

Larvae were feeding from August 23 until November 14, the aver- 
age length of feeding period being 52.10 days. This late date of 
feeding is undoubtedly later than would have been possible in the 
field, for defoliation of peaches occurs previous to this date, al- 
though in the rearing jars the larvae secured the foliage to the twigs 
by the silken webs in such a way that it could not drop. 

CocooNiNG OF Second-Bkood Larv.e. 

Although cocooning normally takes place in the soil, 13 of 361 
individuals recorded pupated in the webbed foliage in which they 
had lived as larvse. These pupae were closely rolled in the individual 
leaves but not attached to them, and no cocoons were formed. The 
dates of cocooning are shown in Table X. 

SUMMARY OF SEASONAL-HISTORY STUDIES. 

Table XI shows a summary of the seasonal-history studies made 
on material in rearing cages during the seasons of 1915 and 1916. 



Table XI. — Summary of seasonal-histori/ studies of the striped peach worm as 
observed by rearing during the seasons of 1015 and 1916. 



Observation. 



Season. 



Number 
of indi- 
viduals. 



Number of days. 



Average. 



Maxi- 
mum. 



Mini- 
mum. 



Length of life of moths of spring brood 

Incubation of eggs ol first brood 

Feedmg period of transforming larvse of the first brood. 

Feeding period of wintering lar\'a^ of the first brood 

Length of period in cocoon of first brood 

Incubation of eggs of second brood 

Feeding period of second-brood larvne 



1916 
1915 
1916 
1916 
1916 
1915 
.1915 



20 
118 
14 
23 
17 



10.6 

13. 18 

29.6 

34.2 

12.4 

15. C. 

52.1 



12 



BULLETIN 599, U. S. DEPARTMENT OF AGRICULTUEE. 



PARASITES. 

While conducting the seasonal-history studies, it was found that 
the striped peach worm was parasitized by a number of insects. 
Table XII records the emergence of the Hymenoptera and Diptera 
which parasitized the 683 larvse collected on sand cherry July 28, 
1915, and 60 pupae collected in May, 1916. 

Table XII. — Emergence of parasites of the striped peach worm (Gelechia con- 
fusella), Benton Harbor, Mich., 1915 and 1916. 



Date of 
emergence. 


Number of 
parasites. 


Date of 
emergence. 


Number of 
parasites. 


liate of 
emergence. 


Number of 
parasites. 


Diptera. 


Hymen- 
optera. 


Diptera. 


Hymen- 
optera. 


Diptera. 


Hymen- 
optera. 


1915. 
Aug. 12... 
Aug. 13... 
Aug. 14... 
Aug. 15... 
Aug. 17... 
Aug. 18... 
Aug. 19... 
Aug. 21... 
Aug. 22... 
Aug. 23... 
Aug. 25... 
Aug. 27... 
Aug. 28... 
Aug. 29... 
Sept I... 







1 





1 









3 
3 
1 

4 
1 
1 
2 
2 
4 
1 
1 
1 
2 
1 
1 


1915. 
Sept. 2... 
Sept. 3... 
Sept. 4... 
Sept. 10. . 
Sept. 11.. 
Sept. 12.. 
Sept. 14.. 
Sept. 15. . 
Sept. 26.. 
(') 

1916. 
June 11... 
June 13... 
June 15. . . 



1 

1 


2 

1 


1 

5 
2 


1 

1 

I 

4 

1 

2 


1916. 
June 18. . . 
June 23. . . 
June 25... 
June 29. . . 
July 2.... 
July4.... 
July 7.... 
July 10... 
July 12... 
July 13... 
July 14... 
(') 

Total.. 


3 
3 
1 
9 

12 
9 

10 

14 
2 
6 
9 

17 






























108 


40 







1 No record. 



The hymenopterous parasites were identified by Mr. R. A. Cush- 
man, of the Bureau of Entomology. Of 40 specimens submited, the 
different genera and species were represented as shown in Table XIII. 



Table XIII.- 



-Parasites reared from the striped peach tvorm. (Gelechia con- 
fusella), Benton Harbor, Mich., 1915 and 1916. 



Parasite, order and family. 


Number 
of indi- 
viduals. 


Stage of host col- 
lected. 


Parasite 
emerged from— 


HYMENOPTERA. 

ICH^fEUMONroAE. 

A ngitia discoocellellae Vier 


20 
1 
1 
1 

8 
2 
7 

2 
61 

2 


Larva. 


Pupa. 




do 






do 


Do. 




do 


Do. 


Braconidae. 


do 


Pupa. 




do 






do 


Do. 


DIPTERA. 

Tachinidae— 


do 


Pupa. 




Larva and pupa. . . 
Pupa 


Do. 


BOMBVXnDAE— 


Do. 









THE STRIPED PEACH WORM. 



13 



The dipterous parasites which emerged in 1915 were identified by 
Mr. Harrison E, Smith, of the Bureau of Entomology, and those 
emerging in 1916 were identified by Mr. W. R. Walton, Entomologist 
in Charge of Cereal and Forage Insect Investigations. 

REMEDIAL MEASURES. 

Experiments were conducted in 1916 to determine the efficacy of 
arsenical sprays in the control of the striped peach worm. Plats 
were laid out in a sand-cherry thicket and sprayed with arsenicals 
according to the formulas in Table XIV, all of the adjoining sand 
cherry serving as checks for comparison. 

Table XIV. — Experiments for control of the siriped peach loorm, Benton 

Harbor, Mich., 1916. 



Plat 
No. 


Formula used. 


Date of 
spraying. 


Result of spraying. 


1 
2 
3 


Arsenate of lead powder, 1 pound to 50 gallons.. 

water. 
Arsenate of lead powder, U pounds to 50 gallons 

water. 
Check ; unsprayed 


June 29 
...do 


5 per cent of terminals webbed. 
3 per cent of terminals webl^ed. 
90 per cent of terminals webbed. 







At the time of spraying, a few of the larvae had hatched and 
webbed a few terminals. The spray material was applied with a 
small compressed-air sprayer at a pressure of 70 pounds and sprayed 
just to the drip. The results of the spraying were very conclusive 
and both sprayed plats were almost entirely free from infestation 
when observed on September 19. 



RECOMMENDATIONS. 

The occurrence of the striped peach worm may be so local as to 
permit of the cutting out of the infested terminals or branches, and 
it will probably not occur in damaging numbers in orchards that are 
sprayed regularly with arsenicals for control of the plum curculio. 
Should the infestation be such as to warrant spraying, it is probable 
that a single application of arsenate of lead paste 2 pounds, or pow- 
der 1 pound, to 50 gallons of water to which 2 pounds of freshly 
slaked lime is added, applied when the first webbing of the leaves 
appears, will satisfactorily control this insect. 



14 BULLETIN 599^ U. S. DEPARTMENT OF AGEICULTUEE. 

LITERATURE CITED. 

1. Chambers, V. T, 

1875. Tineina of the United States. In Ciiicinuati Quar. Jour. Sci., v. 2, 
no. 3. p. 226-259. 
Page 251 : Original description of adult of Oclcvliia confusella. 



1878. Index to the Described Tineina ol" tlie Uniteil States and Canada. 
In U. S. Geol. and (4eog. Snrv. Terr., v. 4, p. 125-167. 
Page 142 : Lists Oelechia confusella Cham. 

3. Smith, J. B. 

1891. List of tlie Lepidoptera of Boreal America. 124 p. Philadelphia. 
Page 100 : Lists Gelechia confusella Cham, as No. 5342. 

4. Pettit, R. H. 

1899. Some Insects of the Year 1898. Mich. Agr. Coll. Exp. Sta. Bui. 175, 
p. 341-373, 20 fig. 

Pages 347-349 : First record of the injury by the larvae with notes on feeding 
habits and pupation. Description of larva and illustrations of larva and pupa. 
Remedies suggested. 

5. MUKTFELDT, MaKY E. 

1899. Description of adult of Deprcssaria pcrsicaeella, sp. nov. In Mich. 
Agr. Coll. Exp. Sta. Bui. 175, p. 348. 

6. MUBTFELDT, MAKY E. 

1900. New Tineidae, with life histories. In Canad. Ent., v. 32, no. 6, p. 
161-166. 

Pages 164-166 : Deprcssarla pcrsicaeella Murt. to Gelechia and makes slight 
corrections in description of adult. 

7. Dyar, H. G. 

1902. A list of North American Lepidoptera. U. S. Nat. Mus. Bui. 52, 
723 p. 

Pago 511 : Lists Gelechia confusella Cham, as No. 5719 with synonym persi- 
caeella Murt. 

8. BuscK, August. 

1903. A revision of the American moths of the family Gelechiidae, with 
descriptions of new species. In Proc. U. S. Nat. Mus., v. 25, p. 767-938, 
pi. 28-33. 

Page 859 : Lists Oelechia confusella Cham, with synonyms Depressaria pcrsi- 
caeella Murt. and Gelechia perslcaeella Murt. 

9. Pettit, R. H. 

1904. Insects injurious to fruits in INIichigan. Mich. Agr. Coll. Exp. Sta. 
Special Bui. 24, 79 p., 70 fig. 

Page 57 : Brief description of larva and moth, habits of larvae with place of 
pupation. Suggests remedies. 

10. GOSSARD, H. A. 

1911. Fall manual of practice in economic zoology. Ohio Agr. Exp. Sta. 
Bui. 233, p. 53-164. 13 pi. 

Page 125 : Notes that Gelechia confusella will probably occur in Ohio in the 
future. 

11. Slingerland, M. v., and Crosby, C. R. 

1914. Manual of Fruit Insects. 503 p., 396 fig. New York. 

Page 287 : Brief description of larva and moth, habits of larvae and recommenda- 
tions for control. 



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